No abstract

No abstract

Strong emission from the auroral green line O( 1 S) G O( 1 D) at 557.7 nm was observed in the afterglow of an atmospheric-pressure 2.45 GHz microwave-induced plasma jet. The device used Ar as the working gas for the plasma, and a surrounding N 2 gas flow to stabilize the discharge. The characteristic line-shape of the peak at 557.7 nm indicated that the emission was from the O( 1 S)N 2 excimer. Vibrational temperatures of NO and N 2 , estimated based on the emission spectra of the afterglow, were compared against the intensity of the green line and the concentration of N 2 gas flowing in the system. The data points yielding the most intense green lines fall at vibrational temperatures of around 2000 K for both NO and N 2 . It was observed that the amount of N 2 gas flowing in the system positively contributed to the intensity of the green line. Using fluid simulation, the O 2 concentration in the afterglow was estimated to be in the range of 1-5.5%.